Method for manufacturing silicon carbide substrate

Abstract

A method for manufacturing a silicon carbide substrate includes the steps of: preparing an ingot made of silicon carbide; obtaining a silicon carbide substrate by cutting the ingot prepared; etching a silicon surface of the silicon carbide substrate; and polishing the etching surface of the silicon carbide substrate after etching the silicon carbide substrate. The step of etching a silicon surface of the silicon carbide substrate includes the step of removing silicon atoms, which form the silicon carbide, from an etching region using chlorine gas, the etching region including the etching main surface of the silicon carbide substrate.

What is claimed is: 
     
         1 . A method for manufacturing a silicon carbide substrate, comprising the steps of:
 preparing an ingot made of silicon carbide;   obtaining a silicon carbide substrate by cutting said ingot prepared;   etching one main surface of said silicon carbide substrate; and   polishing the one main surface of said silicon carbide substrate after etching said silicon carbide substrate,   the step of etching said one main surface of said silicon carbide substrate including the step of removing silicon atoms, which form said silicon carbide, from an etching region using a gas including halogen atoms, said etching region being a region including said main surface of said silicon carbide substrate.   
     
     
         2 . The method for manufacturing the silicon carbide substrate according to  claim 1 , wherein
 in the step of removing said silicon atoms, the silicon atoms forming said silicon carbide are removed while carbon atoms forming said silicon carbide remain in said etching region.   
     
     
         3 . The method for manufacturing the silicon carbide substrate according to  claim 1 , wherein
 the step of etching said one main surface of said silicon carbide substrate further includes the step of removing carbon atoms, which form said silicon carbide, from said etching region from which the silicon atoms have been removed, using an oxidizing gas after the step of removing said silicon atoms.   
     
     
         4 . The method for manufacturing the silicon carbide substrate according to  claim 3 , further comprising the step of substituting the gas including said halogen atoms with an inert gas after the step of removing said silicon atoms and before the step of removing said carbon atoms. 
     
     
         5 . The method for manufacturing the silicon carbide substrate according to  claim 1 , wherein
 in the step of removing said silicon atoms, the silicon atoms forming said silicon carbide are removed from said etching region using chlorine gas or hydrogen chloride gas.   
     
     
         6 . The method for manufacturing the silicon carbide substrate according to  claim 1 , wherein
 said silicon carbide substrate obtained in the step of obtaining said silicon carbide substrate has a diameter of 100 mm or more.   
     
     
         7 . The method for manufacturing the silicon carbide substrate according to  claim 1 , wherein
 in the step of etching said one main surface of said silicon carbide substrate, said main surface of said silicon carbide substrate is etched at a temperature of not less than 800° C. and not more than 1100° C.   
     
     
         8 . The method for manufacturing the silicon carbide substrate according to  claim 1 , wherein
 in the step of etching said one main surface of said silicon carbide substrate, said main surface of said silicon carbide substrate is etched at a pressure of not less than 1 Pa and less than 100 kPa.